Stephen wilcox



artnr rrr' sriirunn wpILcoX, Jn., or wnsTEeLY, uuonnlisnnnn.

IMPROVEMENT IN HOT-AIR ENGHNESJ Specification forming part of LettersPatent N0. 437,759, dated May 16, 1865; antedated May 5, 1865.

1b @ZZ whom it may concern.-

Be it known that I, STEPHEN WILGOX, Jr., of Westerly, in thecountyofWashington and State of Rhode Island, have invented certain new anduseful Improvements in Hot-Air En# gines; and I do hereby declare thatthe following is a full and exact description of the construction andoperation of the same.

The accompanying drawings form a part of this specification.

Figure 1 is a vertical section showing the arrangement of all theprincipal parts. lt is a section on the line S S in Fig. 2. Fig. 2 is aplan view; and Fig. 3 is a front view of the door and its connections,showing the peculiarities therein.

'lhe drawings represent the novel parts, with so much of the other partsas is necessary to exhibit their relation thereto.

Similar letters of reference indicate like parts in all the drawings.

My engine isofthe class in which the fire is subjected to pressure, andthe gaseous products of combustion are passed through theworkingcylinder. The air to support combustion is forced in by a pump.My engine is in these general features similar to that de scribed in theEnglish patent of Sir George Cayley, dated about 1830.

Y My invention relates, rst, to a certain novel use of a variableexpansion-gear, so as to increase the working-pressure; second, to acertain construction and arrangement ofthe parts ofl suchexpansion-gear; third, to certain means for automatically controllingthe proportions of hot and cold air used; fourth, to certainarrangements for absorbing and utilizing the heat due to compression;fth, to

certain means of relieving an engine from pressure, preparatory toreplenishing the lire, or the like; sixth, to a certain construction andarrangement ofthe door and its connections to 4aid in keeping the sametightly fitted; and, seventh, to certain means of protecting from injurythe ground delicate surfaces around the door.

Toenable others skilled in the art to make and use my invention, l willproceed to describe its construction and operation by the aid ofthedrawings, and of vthe letters ot ref erence marked thereon.

Ais the cylinder; a, the piston, provided with a trunk, af, which slidesthrough a stuff` ingbox in the head of the cylinder A. The upper side ofthe piston a serves as a pump to receive and force in air to supply thecombustion in the heater B, while the lower side of the piston a, servesto receive the pressure of the heated and expanded products ofcombustion to impel the engine.

D is the main shaft, provided with a flywheel and crank. E is a stoutrocking shaft, mounted on a Xed framing above, and provided with arms `EE2, as represented, adapted to receive the motion from the pistonathrough the connection a2, and to transmit the power to the crank onthe shaft D through the connection e, as will be obvious. Witheachdescent of the piston a and its connections air is drawn in throughan inhaling-valve, F, and fills the space above the piston. With eachascent of the piston the inhalingvalve F closes, and the air is forcedout through a deliverywalvc (not represented) into apassage, G, (seeFig. 2,) and forced down through the regenerator K. From the base ofthis regenerator it issues, partially heated, through a pipe, H, and iscarred into the heater B. The pipe Il has a branch, H', which enters theheater B above the fuel. The main pipe, on the contrary, enters theheater below the fuel. A valve, U, located as represented, is adapted tobe easily 1 turned, so as to throw more or less air below the fuel, asdesired. If much air passes :into the heater below the grate, so as torise through the iire, the fire is increased greatly in intensity. Whenby turning the valve U less is thrown below and' through there, andnearly all the air is thrown in above the re, the combustion iiags, andthe heat becomes less intense. The hot products of Icombustion from theheater B pass (ataconsider able pressure above the atmosphere) throughthe pipe B into t-he valvechest B2. From thence they are delivered intothe lower end of the cylinder A, accordingly as the inductionvalve I isopened an d held open by the mechanism. At'ter performing the duty offorcing up the piston a., the products of combustion are dischargedthrough the corresponding eductionvalve J, which is also operated by themechanism.

The regenerator K, Iprefer to make in the form of an upright cylindricalvessel. Itis iilled with small tubes and introduced in the positionrepresented. The fresh air is compelled to traverse aspace between andaround these tubes on its way into the lower part of the heater, and theproducts of combustion, in escaping from the engine through theeduction-valve J, are compelled to traversethrough these tubes. Theproducts ofcombustion heat these tubes, and the fresh air circulatingthrough the space around them is thereby heated. By the operation ofthis regenerator heat is economized by being transferred from theoutgoing t-o the ingoing air, in a manner which will be appreciated bythose familiar with air-engineering.

L is an eccentric fixed on the shaft D and connected through theeccentric-rodi to an arm on the rocking-shaft M. On this rocker M aretwo toes, m mf, which are adapted to lift the induction-valve I and theeduction-valve J through their respective rods at the proper times.

I will now describe the features to which my invention more particularlyrelates.

N is a bell-crank lever pivoted on the valvestem t' of theinduction-valve I by the pin n.

O is a lever having a fulcrum or pivot at o and high shoulder, O',adapted to lift the bellcrank lever N and its attachments whenever thetoe m on the rock-shaft M rises, and to support it until the relation isdisturbed.

P is a movable stop adjustable upon the upright rod p, and adapted toreceive and be struck by the horizontal arm of the bell-crank lever, andto hold the latter down, so as to turn the said lever partially aroundand cause its lower end to slip off from the shoulder O. So soon as thisoccurs the valve ceases to be supported by the bell-crank, and falls,carrying the latter with it. This action may be induced earlier or laterinthe stroke, according as the stop I is adjusted higher or lower.

In all conditions of the parts the inductionvalve will be elevatedsimultaneously with the commencement of the upward stroke of the pistona but when the stop O is highest the said Valve I will not be tripped,but will be returned toits seat at the time the piston has aboutcompleted its upstroke, thus performing a full stroke, or nearly so,under the direct .pressure of the products of combustion from the heaterB, while if the stop P is set lower the said induction-valve I will beliberated at a certain period by the slipping olf of the lever-N fromthe shoulder O. The induction-valve I, so soon as free, will fallrapidly, and have the effect to cut off the admission of gases to thelower portion of the cylinder A some time before the end ofthe stroke.By raising and lowering the stop P to different extent-s the period atwhich the cut-oft' takes place may be adjusted with great nicety. Byallowing the stop P to stand at its highest position, and following thepiston with the gases from the heater in a continuous current during thefull stroke, I allow a certain amount of pressure to accumulate in theinterior of the engine. The effect of lowering` the stop P, so as to cutoff early, is to accumulate a higher pressure therein, because, whilethe supply of air thereto remains the same, a smaller volume of air istaken away at each stroke. The heat in the furnace is increased inconsequence ofthe higher pressure of the air therein. It is wellestablished that the combustion of fuel under a high pressure induces agreater intensity of heat than the burning of the same fuel under a lowpressure. The cause is generally ascribed to the closer approximationofthe particles of the air, which facilitates the union of greatquantities of oxygen with the fuel very rapidly. In consequence of thegreater intensity of the heat in my furnace, the combustion is moreperfect and complete. In other words, the admission of air above thegrate to consume the carbonie oxide and the hydrocarbons and particlesof free carbon is made more effectual, and all the fuel used is morecompletely burned, and I believe that less free oxygen necessarilyescapes.

The variations in the point of cut-olf necessary to control the engineare slight, and I work habitually with a much higher pressure in thefurnace than has previously obtained in such engines. I can adjust theposition of the stop P, by a fly-ball or other automatic governor, (notrepresented,) so as to make the speed self-adjusting, and can manage itin all respects as I would an adjustable cut-oif of similar character ona steam-engine.

Q is a controlling-chamber or valve-checker.

i2 is a piston xed on the top of the induction-valve rod t', and adaptedto't easily in the cylindrical interior ofthe controlling-chamber Q.

q is a hole in the lower end ofthe controlling-chamber Q, and i3 is ascrew-plug tapped through the piston i2, and providedwith a slender neckwhich extends downward through the hole q, and is adapted to be acted onby a wrench applied above. Above this slender neck the screw-plug t" isot' such size as to very nearly fill the hole q. VVheu the valve I isliberated, it falls rapidly, in obedience to gravity and to the springi4, until the thick part of the screw-plug i3 enters the hole q, andthereby checks the rapid escape of the air in the bottom of thecontrolling-chamber Q. The air remaining below the piston i2 in thecontrolling-chamber Q then commences to act by its elasticity, therebyresisting compression, and consequently resisting the descent of theinduction-valve I. By turning the screw-plug i3, so as to increase anddiminish the resistance of the air in this manner at pleasure, I am ableto allow a very rapid closing of the 'induction-valve I withoutexperiencing any sensible slamming 011 its seat.

R (see Fig. 2) is la slender vessel containing mercury. It is insertedin the hot products of combustion flowing through the pipe B', and isconnected by the pipe r to the space beneath the loaded diaphragm T.This diaphragm is connected through the lever t and connection t withthe lever a, which operates the freely-turning valve U. The latter, asbefore explained, directs more or less of the fresh air below the grate,and consequently urges the fire more or less, according as the lever tiselevated or depressed. The effect is to `regulate the temperature of theissuing gases so as never to exceed the heat the working-cylinder canendure, and to maintain a great uniformity under all conditions.

V (see Figs. 'l and 2) is a small single-acting pump operated by theconnection r from the rocking lever E2. It is supplied with waterthrough a pipe, e3, from a tank, (not represented,) and at each descentof the piston a its contents are discharged into and caused to minglewith the air in the upper part ofthe cylinderA. When the piston a rises,it compresses the air above it, and thereby develops much heat, whichheat is absorbed in part by this water. The water thus heated isultimatelydischarged with the air through the pipe Gr into theregcnerator K, where the heat th us received becomes available to aid intransforming it into steam, which steam passes, thus mingled with theair, into and through the heater B.

It is generally known that water or steam in small quantities does notprevent, but promotes combustion. I do not believe that it is itselfactually burned; but l believe, as the result of much observation, thatits presence promotes the union of the oxygen with the other matterpresent, and reduces the quantity of free oxygen passing away up thestack. The steam introduced in the manner above described also adds tothe quantity of the gaseous matteracting on the piston, and therebytends to add to their pressure. It also contributes by its effect on theadhesion of the burning' fuel or ashes, or in some way not wellunderstood, to the clearness of the lire. The water introduced by thepumps V therefore performs several important functions first, it lowersthe temperature of the compressed fresh air in the upper part of thecylinder A, and thus reduces the resistance to its compression, andallows the use ot' leather or other delicate packing,and ot'correspondingly delicate valves at that point;` second, it keeps thecylinderA and piston a cool, and thus by keeping the air cool while itis inhaled allows the reception of a larger qualitity of fresh air ateach stroke; and, third, it supplies moisture, in the form either ofsteam or of water highly heated, to promote the combustion and increasethe pressure of the gaseous matter.

The capacity of the pump V is so small that an excess of water can never,be delivered above what can be disposed of by the engine; but it ma-ybe of advantage sometimes to reduce the quantity much below `thefullcapacity of the pump.

V is the handle by which is adjusted a stop-cock, V2, in the pipe V8,through which pipe water isreceived by the pump` V from a tank.(Notrepresented.) Thecock Vis usually half closed. By opening farthermore water isdelivered into the pump, and by shutting it closer lesswater is so delivered.

My furnace B is always supplied` with a thick bed of coal, and the wholeof its nre-brick surfaces are very intensely heated; but the supply ofair, being all forced in through the pumping operation, is necessarilylimited, and

this limits the rate of combustion.

The addition of small quantities of water increases the heat of thelire, as above eX- plained.

I believe that more moisture can be introduced with benefit into theheated gases to act mechanically as simply steam than it will usually beadvisable to admit with the air to support combustion. In order toeffect this, I provide means for supplying water in certain quantitiesthrough another channel, which will be described further on, with thenovelties which I have invented in connection therewith.

W is a hand-leverturning on the center w, and adapted by changing itsposition to press inward, and consequently to throw out of use theinhaling-valve F atwill. When this lever W is erect, as represented, itallows the engine to perform and operate with a considerable pressure inits interior, as described; but so soon as it is depressed into theposition indicated in red outline it holds the inhalingvalve Fconstantly open, and allows the air which is inhaled by the downstrokeof the piston ato be freely exhaled through the same passage by theupstroke ofthe same. I n. this condition the engine immediately losesits pressure. This is desirable at times for brief periods, especiallyfor tiring the furnace.

I propose, where two cr more of my engines areapplicd to rotate onecommon shaltpto adopt this mode of relief to each engine alternately,and, replenishing the furnace thereof with coal, or elevating the handleW to the position indicated by the dark lines, the air inhaled isimprisoned and compressed, because the inhaling-valve F now closesduring the upstrole ot' the piston a, and the pressure within the enginerises to its proper working' stage. i

X X are the doors through which the coal is introduced and the ashesremoved. Y

Z is an arm hinged in the .usual manner to the side of the door-frame byhinges. (Not represented.) A stout hollow bolt, w, is tapped through thearm Z, and carries in its interior a cylindrical stem, w', which isfixed to the center of the door X. A shoulder or head, w1", near theouter end of the stem x', rests against` the outer face of the arm Z. 0nturning the hollow bolt lorso as to move it outward the door X is drawnoutward, and the bar or arm Z may then be raised'slightly, like a stoutlatch, and the door be opened. After the tire has been properly attendedto, the door is` closed by swinging around on the hinges Z', and islatched, as before. Next, by turning the hollow'bolt in the oppositedirection, so

as to move it inward, the slackjs all taken up and .the door is pressedvery tightly to its seat, so as to endure the pressure in the interiorof the furnace without allowing any sensible leakage. The hollow bolt isprovided with a handle or arm, as represented, to allow it to beconveniently operated in either direction to confine or release the doorX. The door is circular. around the center-pin fr is screwed outward, asdescribed, it holds the door X loosely; but by turning it inward a fewthreads it is tightened. In the loosened condition of the parts the doorX may be turned around by the aid of a dog screwed upon the rod andground upon its seat, in a manner familiar to engineers, in order to tthe surfaces of the door and of the door-frame tightly together. The dogmay be of any convenient form. One form is represented in red outline.

Y is the surface of the door-frame, which is thus ground smooth toreceive the corresponding surface, X, of the door.

Y is a lip or-iiange which projects outwardly adjacent to the surface Yiu the manner represented. v

X is a lip which projects inwardly from the door in the positionrepresented. The purpose of these lips X and Y is to defend and protectthe delicately-ground surfaces X and Y of the door and door-frame whenthe door is standing open.

It is found in practice that unless some such provision is made thefinely-ground surfaces are liable to be struck by the coal or by theshovels or other tools employed and so seriousl y marred as to preventtheir fitting tightly together without very frequent grinding.

I will now conclude the description of my apparatus by indicatingthemcans whereby I manufacture steam to mingle with the products ofcombustion, in addition to that made from the water injected through thepipe v4. These means are very simple. l is a pump operated by aconnection from an arm, E2, on the main roekingshaft E. 2 is a pipeleading water to the pump lfrom atank. (Not represented.) 3 is astop-cock in the pipe 2, adapted to control the amount of water admittedto the pump l, it being intended that the pump shall usually receive notso much as its capacity would admit. 4 is a delivery-pipe which throwsthe water from the pump l into the heated gases. 5 is a broad andshallow pan adapted to receive the water from the pipe 4, and from whichpan the water is rapidly evaporated. I have represented this pan aslyingA immediately upon a fire-brick diaphragm within the heater. rIhewater may be admitted in a iine shower upon this pan or upon a panwithin the pipe B', which leads to the valve I, as may be foundpreferable. In either position it is evident that the intensely-heatedproducts of combustion will give up a portion of their heat to the waterand cause the production of steam, and that the effects will be When thehollow bolt x' to lower the temperature of the gases directly and toproduce a mixture of air and steam the temperature of which will bestill lower, while the volume or the pressure will be augmented by theaddition of the steam. Ihe effect is to yield a greater power and tocause the working parts of the engine to endure better.

I regulate the heat of the products of combustion passing through pipe Bto the engine by varying the quantity of water admitted. If my cock V2is opened so as to throw more water into the heater B, the temperatureof the products of combustion is diminished. In this con vlition I canwithout injury to any part put all the air through the fire by driving'it all through the lower branch, H, instead of driving a part throughthe upper branch, H', of the air-pipe. When this is effected, eitherautomatically or by hand, the power' of my en gine is, of course, verygreatly increased. The reverse movement of the handle V, by reducing theopening of the cock V2, has the effect to raise the temperature in theapparatus and to diminish the power of my engine. When the engine workstoo weakly or too slowly, I open the cock V2 a little farther and admitmore water and generate a larger volume of steam. When the engine workstoo strongly or too rapidly, I shut the cock V2 more closely and admitless water, and consequently produce a smaller volume of steam. I thuscontrol the power of the engine by this means. Substantially the sameeifect would result from adjusting the cock 3 so as to admit more orless water at the other point-to wit, directly into the heater B, inlieu of through the regenerator K and connections. I prefer for severalreasons to vary the supply at that point, instead of at the one abovedescribed. One reason is, that as the water introduced through the pumpV has a duty to perform of absorbing the heat of compression, which isnearly uniform, it is well to make it of small size and allow it to bealways filled. The other may be larger, as above described, and may workusually'only part full. I therefore consider the cock 3 the usualregulating-cock for my en gine.

I apply to my apparatus a safety-valve, (not represcnted,) to provideagainst an yoverpressure in any possible contingency. I take care tomaintain so high a temperature that the vapor is always dry andsuperheated.

Some of the advantages due to certain features of my invention may beseparately enumerated as follows First. By reason of my variable cut-offmechanism, related as described to an engine operating by the pressureof the gases in the combustion-chamber or heater, I am able, by varyingthe degree of expansion of the products of combustion in lthe cylinder,to control the power at will, so as to regulate the speed and toaccumulate the pressure in the engine, and to work generally at a higherpressure and attain more perfect combustion than is possible with thepreviously-known modes of controlling the power of such engines.

Second. By reason of the employment of my controllingchamber Q, hole g,-controllingpiston 2, a-nd screw-plug 3, related as described to thevalve I and its connections, I am able to adjust and control the descentor drop of the valve I, so as toallow it to close very rapidly andwithout slamming, by the aid of very simple and durable mechanism, andwithout the necessity for any water or other dense iiuid.

Third. By reason of my mercury-vessel R being subject to the heat of theproducts of combustion, and connected by the pipe r, so as by its vaporto operate the loaded diaphragm T and its connections, and of my lever tbeing connected so as to operate the valve U, as described, I am able toregulate the temperature of the gaseous matter flowing to the cylinderA, so as to' avoid burning or injurin g the working parts. This portionof my invention may be used either alone or in connection with othermodes of regulating heat.

Fourth. By reason of the fact that the water delivered through the cockY2, to absorb the heat of compression and add by its expansive force tothe working-power of the engine, is delivered at each stroke by gravitythrough the passage G, I avoid the accumulation of water in theworking-cylinder, and conse# quently the shocks and danger of fracturewhich attend the performance of such double function in the manner shownin the English patent of 1858, No. 969.

Fifth. By reason of the fact that my inhaling-valve F can by the meansdescribed be held open during the complete revolution of the engine atwill, I am able very readily to relieve the interior of the engine frompressure and allow the door to be opened to supply fuel or the like, andalso insure the cooling' ofthe upper port-ion of the cylinder- A andpiston ct by the active circulation of the air during such process. Byreleasing the inhal- 1ng-valve I can set the engine in full operation sosoon as the door is again secured. I afict both of these operations withvery little a or.

Sixth. By reason of the fact that my door Xis circular and is connectedto the stout hinged bar Z only by the hollow bolt and stem mf, I amable, by a very simple construction of the parts, to insure that thedoor may be opened and closed very easily and when closed may retain thegases very tightly, and to very readily release the door and grind itupon its seat by rotating or partly turning it around backward andforward around its center a," with little labor and delay.

Seventh. By reason of my lip X adjacent to the ground surface X on thedoor and my lip Y adjacent to the ground surface Y on the door-frame, Iprotect the ground surfaces effeetually against all the ordinaryviolence which tends to indent and abrade such surfaces.

Having now fully described my invention, what I claim as new therein,and desire to secure by Letters Patent, is as follows:

l. In combination with an engine in which the combustion is conductedunder the workin g-pressure, the employment of an adjustablecut-offmechanism arrangedV to operate therewith substantially in themanner and for the purposes herein set forth.

2. The controlling-chamber Q,orif1ce g, and screw-plug 3, arrangedrelatively to thepiston 2 and to the induction-valve I and itsconnections substantially as and for the purpose herein set forth.

3. The combination of the thermostat R T, or its equivalent, with theregulating-valve U, the two channels H and Hf, and the engine A a, thewhole being so arranged as to automatically control the proportions ofair relatively to the gaseous products of combustion actuating theengine, substantially in the manner and for the purpose herein setforth.

4. The pump V and pipes ci and G, or their equivalents, arrangedrelatively' to the compressing parts A a and heating parts B, &c., ortheir equivalents, substantially as herein described, so that I cancause the water to perform the several functions in the manner hereinset forth.

5. The arrangement of the inhaling-valve F and lever W, or itsequivalent, substantially as and for the purpose herein set forth.

6. Connecting the circular door X to the hinged bar or arm Z by thehollow bolt .c and stem x', or their equivalents, so that the door maybe readily released and ground and again secured, in the mannersubstantially as herein set forth.

7. The guard-lips X and Y', arranged relatively to the door X of thefurnace and to the ground surfaces on the same and on the doorframe Y,substantially as and for the purposes herein set forth.

STEPHEN WILCOX, JR.

